777
FXUS63 KDTX 121019
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
619 AM EDT Thu Sep 12 2024

.KEY MESSAGES...

- Fog, locally dense, will be possible during the morning periods
over the next few days.

- Seasonally warm and dry conditions prevail through the rest of the
week and the weekend.

&&

.AVIATION...

The lake moisture plume early this morning has not had the coverage
compared the last couple days. Much of it has been focused south of
metro. Shallow radiational fog has however been expanding in
coverage with the approach of daybreak. This has been more impactful
at PTK and FNT, with the urban heat island likely keep minimal fog
coverage at the Detroit terminals. Like the last couple of days,
morning fog will lift quickly between 12 and 13Z, leaving VFR
conditions through the day. The weak gradient overhead will yield
only light easterly winds during peak daytime heating.

For DTW/D21 Convection...No thunderstorms are forecast through the
TAF period.

 DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 345 AM EDT Thu Sep 12 2024

DISCUSSION...

Latest Nighttime Microphysics satellite imagery supports that shallow
ground based fog is developing across eastern sections of the
forecast this morning. Surface T/Td spreads remain decent yet in
some locations, particularly the urban heat island of Metro Detroit.
Will monitor observations this morning and issue Speical Weather
Statements or a Dense Fog Advisory as needed.

Geopotential heights will build, H5 at +590 dam, over the Great
Lakes, Northeastern United States and much of Ontario/Quebec for the
end of the week and this weekend. Medium range guidance is in strong
agreement that a ridge centroid will flank the remnants of Francine
and become a dipole with Southeast Michigan remaining under the high
pressure influence. A very good setup for persistence forecasting.
Did introduce Areas of fog wording for each the morning periods
through Sunday. The strong model consensus gives high confidence in
seasonable warmth and dry conditions for much of the period. Did
incorporate EC-AIFS as a basis for much of the temperature forecast.
Daytime highs are expected to reach the lower to middle 80s which is
roughly 7 to 10 degrees above normal.

MARINE...

Broad high pressure centered over the Northeast continues to
dominate conditions for the central Great Lakes through the
remainder of the week. Lighter winds (generally below 15kts) persist
for this timeframe predominately from the southeast, though some
variability between more pure southerly or easterly likely. Dry
conditions also hold as the remnants of Francine expected to stall
well south of the region.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....SC
DISCUSSION...CB
MARINE.......KDK


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at www.weather.gov/detroit.